Cloud computing

1. Definition

1.1. On-demand delivery of computing resources over the internet

1.2. Pay-as-you-go pricing

1.3. Shared pool of configurable computing resources

1.4. Eliminates large upfront investments in hardware

1.5. Shifts from traditional on-premises models

2. Benefits

2.1. Cost-Efficiency: Pay-as-you-go model, reduces CapEx, economies of scale

2.2. Scalability & Elasticity: Dynamically adjust resources to match demand

2.3. Flexibility: Enables remote work and multiple deployment models

2.4. Reliability: Data backup, disaster recovery, fault tolerance

2.5. Speed & Agility: Rapid resource deployment and management tools (AWS CLI, API, Console)

2.6. Reduced Management Burden: Cloud providers handle infrastructure maintenance

3. Impact of Cloud Computing

3.1. Shifts IT focus from infrastructure management to business value creation

3.2. Enables agility and innovation

3.3. Preferred choice for organizations seeking efficiency and scalability

4. Core Characteristics

4.1. On-demand self-service: Users provision resources without human interaction

4.2. Broad network access: Accessible over standard network mechanisms (e.g., HTTPS)

4.3. Resource pooling: Multi-tenant model, shared physical hardware

4.4. Rapid elasticity: Automatic scaling (vertical & horizontal)

4.5. Measured service: Pay only for consumed resources

5. Deployment Models

5.1. Public Cloud: Available to the public, owned by third parties (e.g., AWS, Azure, GCP)

5.2. Private Cloud: Exclusive to one organization, managed by internal/external provider

5.3. Community Cloud: Shared among organizations with common concerns

5.4. Hybrid Cloud: Combination of private and public cloud resources

6. Service Models

6.1. Infrastructure as a Service (IaaS)

6.1.1. Access to virtual machines, storage, and networks

6.1.2. Customer controls OS, applications, but not physical infrastructure

6.1.3. Examples: Amazon EC2, Microsoft Azure, Google Compute Engine

6.2. Platform as a Service (PaaS)

6.2.1. Provides platform for application development and deployment

6.2.2. No need to manage underlying infrastructure

6.2.3. Examples: AWS Elastic Beanstalk, Heroku, Google App Engine

6.3. Software as a Service (SaaS)

6.3.1. Cloud-hosted applications accessible via web browsers

6.3.2. Limited control over application settings

6.3.3. Examples: Gmail, Microsoft 365, Salesforce, Slack